【Qt】modbus之串口模式读操作

末蓝、 2023-01-22 11:57 427阅读 0赞

## 00. 目录 ##

### 文章目录 ###

*   *  00. 目录
     *  01. 概述
     *  02. 开发环境
     *  03. 读DiscreteInputs程序示例
     *  04. 读Coils程序示例
     *  05. 读InputRegisters程序示例
     *  06. 读HoldingRegisters程序示例
     *  07. 综合示例
     *  08. 程序下载
     *  09. 附录

## 01. 概述 ##

Qt中几个常用的串口modbus类

QModbusRtuSerialSlave       //modbus串口通信方式下的服务器类
    QModbusRtuSerialMaster      //串口通信方式下的客户端类
    QModbusServer               // QModbusServer类接收和处理modbus的请求。
    QModbusDataUnit             //存储接收和发送数据的类，数据类型为1bit和16bit
    QModbusReply                //客户端访问服务器后得到的回复（如客户端读服务器数据时包含数据信息）

## 02. 开发环境 ##

**Windows系统**：Windows10

**Qt版本**：Qt5.15或者Qt6

Pro配置文件如下

QT       += core gui serialbus serialport
    
    greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
    
    CONFIG += c++11
    
    # You can make your code fail to compile if it uses deprecated APIs.
    # In order to do so, uncomment the following line.
    #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
    
    SOURCES += \
        main.cpp \
        widget.cpp
    
    HEADERS += \
        widget.h
    
    # Default rules for deployment.
    qnx: target.path = /tmp/$${TARGET}/bin
    else: unix:!android: target.path = /opt/$${TARGET}/bin
    !isEmpty(target.path): INSTALLS += target

## 03. 读DiscreteInputs程序示例 ##

**widget.h文件**

#ifndef WIDGET_H
    #define WIDGET_H
    
    #include <QWidget>
    
    //前向声明
    class QModbusClient;
    class QModbusReply;
    
    
    class Widget : public QWidget
    { 
        Q_OBJECT
    
    public:
        Widget(QWidget *parent = nullptr);
        ~Widget();
    
    
    private:
        QModbusClient *modbusDevice = nullptr;
    
    
    private slots:
        void onReadReady();
    };
    #endif // WIDGET_H

**widget.cpp文件**

#include "widget.h"
    #include <QModbusRtuSerialMaster>
    #include <QModbusDataUnit>
    #include <QModbusReply>
    #include <QVariant>
    #include <QSerialPort>
    #include <QDebug>
    
    //构造函数
    Widget::Widget(QWidget *parent)
        : QWidget(parent)
    { 
        //1. 创建QModbusDevice对象
        modbusDevice = new QModbusRtuSerialMaster;
    
        //2. 如果处于连接状态，则断开连接
        if (modbusDevice->state() == QModbusDevice::ConnectedState)
        { 
            //断开连接设备
            modbusDevice->disconnectDevice();
        }
    
        //3. 设置串口相关参数
        //设置串口信息
        modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter, QVariant("COM3"));
        //设置校验 无校验
        modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter, QSerialPort::NoParity);
        //设置波特率
        modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, QSerialPort::Baud19200);
        //设置停止位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, QSerialPort::OneStop);
        //设置数据位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, QSerialPort::Data8);
    
        //4. 设置其他信息
        //设置超时时间
        modbusDevice->setTimeout(1000); //1秒
        //设置失败重试次数
        modbusDevice->setNumberOfRetries(3);
    
        //5. 连接到设备
        bool ok = modbusDevice->connectDevice();
        if (!ok)
        { 
            qDebug() << "连接到串口失败： " << modbusDevice->errorString();
        }
        else
        { 
            qDebug() << "连接到串口成功";
        }
    
        //6. 发送读取数据请求
        //从地址0开始读取10个保持寄存器的值
        //QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);
        //从地址0开始读取10个离散输入量的值
        QModbusDataUnit data(QModbusDataUnit::DiscreteInputs, 0, 10);
    
        QModbusReply* reply = modbusDevice->sendReadRequest(data, 0x1);
        if (nullptr == reply)
        { 
            qDebug() << "发送请求数据失败: " << modbusDevice->errorString();
        }
        else
        { 
            if (!reply->isFinished())
            { 
                connect(reply, &QModbusReply::finished, this, &Widget::onReadReady);
            }
            else
            { 
                //broadcast replies return immediately
                delete reply;
            }
        }
    
        //7. 接收响应
        //通过槽函数实现
    
    }
    
    
    //析构函数
    Widget::~Widget()
    { 
        if (modbusDevice)
        { 
            modbusDevice->disconnectDevice();
        }
    
        delete modbusDevice;
    }
    
    //准备读取数据的槽函数
    void Widget::onReadReady()
    { 
        auto reply = qobject_cast<QModbusReply*>(sender());
        if (nullptr == reply)
        { 
            return;
        }
    
        //判断是否出错
        if (reply->error() == QModbusDevice::NoError)
        { 
            //读取响应数据
            const QModbusDataUnit responseData = reply->result();
    
            qDebug() << responseData.values();
    
        }
        else if (reply->error() == QModbusDevice::ProtocolError)
        { 
            qDebug() << "Read response Protocol error: " << reply->errorString();
        }
        else
        { 
            qDebug() << "Read response Error: " << reply->errorString();
        }
    
    
        //删除reply
        reply->deleteLater();
    }

**执行结果**

15:09:19: Starting D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe ...
    连接到串口成功
    QVector(0, 1, 0, 0, 1, 1, 0, 1, 1, 1)
    15:09:22: D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe exited with code 0

## 04. 读Coils程序示例 ##

**widget.h文件**

**widget.cpp文件**

#include "widget.h"
    #include <QModbusRtuSerialMaster>
    #include <QModbusDataUnit>
    #include <QModbusReply>
    #include <QVariant>
    #include <QSerialPort>
    #include <QDebug>
    
    //构造函数
    Widget::Widget(QWidget *parent)
        : QWidget(parent)
    { 
        //1. 创建QModbusDevice对象
        modbusDevice = new QModbusRtuSerialMaster;
    
        //2. 如果处于连接状态，则断开连接
        if (modbusDevice->state() == QModbusDevice::ConnectedState)
        { 
            //断开连接设备
            modbusDevice->disconnectDevice();
        }
    
        //3. 设置串口相关参数
        //设置串口信息
        modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter, QVariant("COM3"));
        //设置校验 无校验
        modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter, QSerialPort::NoParity);
        //设置波特率
        modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, QSerialPort::Baud19200);
        //设置停止位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, QSerialPort::OneStop);
        //设置数据位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, QSerialPort::Data8);
    
        //4. 设置其他信息
        //设置超时时间
        modbusDevice->setTimeout(1000); //1秒
        //设置失败重试次数
        modbusDevice->setNumberOfRetries(3);
    
        //5. 连接到设备
        bool ok = modbusDevice->connectDevice();
        if (!ok)
        { 
            qDebug() << "连接到串口失败： " << modbusDevice->errorString();
        }
        else
        { 
            qDebug() << "连接到串口成功";
        }
    
        //6. 发送读取数据请求
        //从地址0开始读取10个保持寄存器的值
        //QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);
        //从地址0开始读取10个离散输入量的值
        //QModbusDataUnit data(QModbusDataUnit::DiscreteInputs, 0, 10);
    
        //QModbusDataUnit::Coils 从地址0开始读取10个线圈值
        QModbusDataUnit data(QModbusDataUnit::Coils, 0, 10);
    
    
        QModbusReply* reply = modbusDevice->sendReadRequest(data, 0x1);
        if (nullptr == reply)
        { 
            qDebug() << "发送请求数据失败: " << modbusDevice->errorString();
        }
        else
        { 
            if (!reply->isFinished())
            { 
                connect(reply, &QModbusReply::finished, this, &Widget::onReadReady);
            }
            else
            { 
                //broadcast replies return immediately
                delete reply;
            }
        }
    
        //7. 接收响应
        //通过槽函数实现
    
    }
    
    
    //析构函数
    Widget::~Widget()
    { 
        if (modbusDevice)
        { 
            modbusDevice->disconnectDevice();
        }
    
        delete modbusDevice;
    }
    
    //准备读取数据的槽函数
    void Widget::onReadReady()
    { 
        auto reply = qobject_cast<QModbusReply*>(sender());
        if (nullptr == reply)
        { 
            return;
        }
    
        //判断是否出错
        if (reply->error() == QModbusDevice::NoError)
        { 
            //读取响应数据
            const QModbusDataUnit responseData = reply->result();
    
            qDebug() << responseData.values();
    
        }
        else if (reply->error() == QModbusDevice::ProtocolError)
        { 
            qDebug() << "Read response Protocol error: " << reply->errorString();
        }
        else
        { 
            qDebug() << "Read response Error: " << reply->errorString();
        }
    
    
        //删除reply
        reply->deleteLater();
    }

**执行结果**

15:14:35: Starting D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe ...
    连接到串口成功
    QVector(1, 0, 1, 1, 1, 0, 1, 1, 1, 1)
    15:15:12: D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe exited with code 0

## 05. 读InputRegisters程序示例 ##

**widget.h文件**

**widget.cpp文件**

#include "widget.h"
    #include <QModbusRtuSerialMaster>
    #include <QModbusDataUnit>
    #include <QModbusReply>
    #include <QVariant>
    #include <QSerialPort>
    #include <QDebug>
    
    //构造函数
    Widget::Widget(QWidget *parent)
        : QWidget(parent)
    { 
        //1. 创建QModbusDevice对象
        modbusDevice = new QModbusRtuSerialMaster;
    
        //2. 如果处于连接状态，则断开连接
        if (modbusDevice->state() == QModbusDevice::ConnectedState)
        { 
            //断开连接设备
            modbusDevice->disconnectDevice();
        }
    
        //3. 设置串口相关参数
        //设置串口信息
        modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter, QVariant("COM3"));
        //设置校验 无校验
        modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter, QSerialPort::NoParity);
        //设置波特率
        modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, QSerialPort::Baud19200);
        //设置停止位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, QSerialPort::OneStop);
        //设置数据位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, QSerialPort::Data8);
    
        //4. 设置其他信息
        //设置超时时间
        modbusDevice->setTimeout(1000); //1秒
        //设置失败重试次数
        modbusDevice->setNumberOfRetries(3);
    
        //5. 连接到设备
        bool ok = modbusDevice->connectDevice();
        if (!ok)
        { 
            qDebug() << "连接到串口失败： " << modbusDevice->errorString();
        }
        else
        { 
            qDebug() << "连接到串口成功";
        }
    
        //6. 发送读取数据请求
        //从地址0开始读取10个保持寄存器的值
        //QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);
        //从地址0开始读取10个离散输入量的值
        //QModbusDataUnit data(QModbusDataUnit::DiscreteInputs, 0, 10);
    
        //QModbusDataUnit::Coils 从地址0开始读取10个线圈值
        //QModbusDataUnit data(QModbusDataUnit::Coils, 0, 10);
    
        //QModbusDataUnit::InputRegisters 从地址0开始读取10个输入寄存器的值
        QModbusDataUnit data(QModbusDataUnit::InputRegisters, 0, 10);
    
        QModbusReply* reply = modbusDevice->sendReadRequest(data, 0x1);
        if (nullptr == reply)
        { 
            qDebug() << "发送请求数据失败: " << modbusDevice->errorString();
        }
        else
        { 
            if (!reply->isFinished())
            { 
                connect(reply, &QModbusReply::finished, this, &Widget::onReadReady);
            }
            else
            { 
                //broadcast replies return immediately
                delete reply;
            }
        }
    
        //7. 接收响应
        //通过槽函数实现
    
    }
    
    
    //析构函数
    Widget::~Widget()
    { 
        if (modbusDevice)
        { 
            modbusDevice->disconnectDevice();
        }
    
        delete modbusDevice;
    }
    
    //准备读取数据的槽函数
    void Widget::onReadReady()
    { 
        auto reply = qobject_cast<QModbusReply*>(sender());
        if (nullptr == reply)
        { 
            return;
        }
    
        //判断是否出错
        if (reply->error() == QModbusDevice::NoError)
        { 
            //读取响应数据
            const QModbusDataUnit responseData = reply->result();
    
            qDebug() << responseData.values();
    
        }
        else if (reply->error() == QModbusDevice::ProtocolError)
        { 
            qDebug() << "Read response Protocol error: " << reply->errorString();
        }
        else
        { 
            qDebug() << "Read response Error: " << reply->errorString();
        }
    
    
        //删除reply
        reply->deleteLater();
    }

**执行结果**

15:18:19: Starting D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe ...
    连接到串口成功
    QVector(10, 11, 12, 13, 14, 15, 16, 17, 18, 11)
    15:18:22: D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe exited with code 0

## 06. 读HoldingRegisters程序示例 ##

**widget.h文件**

**widget.cpp文件**

#include "widget.h"
    #include <QModbusRtuSerialMaster>
    #include <QModbusDataUnit>
    #include <QModbusReply>
    #include <QVariant>
    #include <QSerialPort>
    #include <QDebug>
    
    //构造函数
    Widget::Widget(QWidget *parent)
        : QWidget(parent)
    { 
        //1. 创建QModbusDevice对象
        modbusDevice = new QModbusRtuSerialMaster;
    
        //2. 如果处于连接状态，则断开连接
        if (modbusDevice->state() == QModbusDevice::ConnectedState)
        { 
            //断开连接设备
            modbusDevice->disconnectDevice();
        }
    
        //3. 设置串口相关参数
        //设置串口信息
        modbusDevice->setConnectionParameter(QModbusDevice::SerialPortNameParameter, QVariant("COM3"));
        //设置校验 无校验
        modbusDevice->setConnectionParameter(QModbusDevice::SerialParityParameter, QSerialPort::NoParity);
        //设置波特率
        modbusDevice->setConnectionParameter(QModbusDevice::SerialBaudRateParameter, QSerialPort::Baud19200);
        //设置停止位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialStopBitsParameter, QSerialPort::OneStop);
        //设置数据位
        modbusDevice->setConnectionParameter(QModbusDevice::SerialDataBitsParameter, QSerialPort::Data8);
    
        //4. 设置其他信息
        //设置超时时间
        modbusDevice->setTimeout(1000); //1秒
        //设置失败重试次数
        modbusDevice->setNumberOfRetries(3);
    
        //5. 连接到设备
        bool ok = modbusDevice->connectDevice();
        if (!ok)
        { 
            qDebug() << "连接到串口失败： " << modbusDevice->errorString();
        }
        else
        { 
            qDebug() << "连接到串口成功";
        }
    
        //6. 发送读取数据请求
        //从地址0开始读取10个保持寄存器的值
        QModbusDataUnit data(QModbusDataUnit::HoldingRegisters, 0, 10);
    
        QModbusReply* reply = modbusDevice->sendReadRequest(data, 0x1);
        if (nullptr == reply)
        { 
            qDebug() << "发送请求数据失败: " << modbusDevice->errorString();
        }
        else
        { 
            if (!reply->isFinished())
            { 
                connect(reply, &QModbusReply::finished, this, &Widget::onReadReady);
            }
            else
            { 
                //broadcast replies return immediately
                delete reply;
            }
        }
    
        //7. 接收响应
        //通过槽函数实现
    
    }
    
    
    //析构函数
    Widget::~Widget()
    { 
        if (modbusDevice)
        { 
            modbusDevice->disconnectDevice();
        }
    
        delete modbusDevice;
    }
    
    //准备读取数据的槽函数
    void Widget::onReadReady()
    { 
        auto reply = qobject_cast<QModbusReply*>(sender());
        if (nullptr == reply)
        { 
            return;
        }
    
        //判断是否出错
        if (reply->error() == QModbusDevice::NoError)
        { 
            //读取响应数据
            const QModbusDataUnit responseData = reply->result();
    
            qDebug() << responseData.values();
    
        }
        else if (reply->error() == QModbusDevice::ProtocolError)
        { 
            qDebug() << "Read response Protocol error: " << reply->errorString();
        }
        else
        { 
            qDebug() << "Read response Error: " << reply->errorString();
        }
    
    
        //删除reply
        reply->deleteLater();
    }

**执行结果**

14:33:54: Starting D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe ...
    连接到串口成功
    QVector(10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
    14:33:57: D:\ProgramData\Qt\build-Test-Desktop_Qt_5_15_2_MinGW_32_bit-Debug\debug\Test.exe exited with code 0

## 07. 综合示例 ##

程序界面  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RlbmdqaW4yMDEwNDA0MjA1Ng_size_16_color_FFFFFF_t_70]

**settingdialog.h文件**

#ifndef SETTINGDIALOG_H
    #define SETTINGDIALOG_H
    
    #include <QDialog>
    #include <QtSerialPort>
    
    namespace Ui { 
    class SettingDialog;
    }
    
    //串口设置相关类
    class SettingDialog : public QDialog
    { 
        Q_OBJECT
    
    public:
        struct Settings
        { 
            //串口名
            QString serialName = "COM3";
            //校验位
            int parity = QSerialPort::NoParity;
            //波特率
            int baud = QSerialPort::Baud19200;
            //数据位
            int dataBits = QSerialPort::Data8;
            //停止位
            int stopBits = QSerialPort::OneStop;
    
            //响应时间
            int responseTime = 1000;
            //重试次数
            int numberOfRetries = 3;
        };
    
        explicit SettingDialog(QWidget *parent = nullptr);
        ~SettingDialog();
    
        //返回参数设置信息
        Settings  settings() const;
    
    private slots:
        void on_btnApply_clicked();
    
    private:
        Ui::SettingDialog *ui;
        Settings m_settings;
    };
    
    #endif // SETTINGDIALOG_H

**settingdialog.cpp文件**

#include "settingdialog.h"
    #include "ui_settingdialog.h"
    
    //构造函数
    SettingDialog::SettingDialog(QWidget *parent) :
        QDialog(parent),
        ui(new Ui::SettingDialog)
    { 
        ui->setupUi(this);
    
        //设置默认参数信息
        ui->serialNameLineEdit->setText(tr("COM3"));
        ui->parityComboBox->setCurrentIndex(0);
    
        ui->baudComboBox->setCurrentText(QString::number(m_settings.baud));
        ui->dataBitComboBox->setCurrentText(QString::number(m_settings.dataBits));
        ui->stopBitComboBox->setCurrentText(QString::number(m_settings.stopBits));
    
        ui->spinBoxTimeOut->setValue(m_settings.responseTime);
        ui->spinBoxRetry->setValue(m_settings.numberOfRetries);
    
    }
    
    //析构函数
    SettingDialog::~SettingDialog()
    { 
        delete ui;
    }
    
    //返回参数信息
    SettingDialog::Settings SettingDialog::settings() const
    { 
        return m_settings;
    }
    
    //引用按钮槽函数
    void SettingDialog::on_btnApply_clicked()
    { 
        m_settings.serialName = ui->serialNameLineEdit->text();
        m_settings.parity = ui->parityComboBox->currentText().toInt();
        m_settings.baud = ui->baudComboBox->currentText().toInt();
        m_settings.dataBits = ui->dataBitComboBox->currentText().toInt();
        m_settings.stopBits = ui->stopBitComboBox->currentText().toInt();
    
        m_settings.responseTime = ui->spinBoxTimeOut->value();
        m_settings.numberOfRetries = ui->spinBoxRetry->value();
    
        //隐藏参数设置对话框
        hide();
    }

**mainwindow.h文件**

#ifndef MAINWINDOW_H
    #define MAINWINDOW_H
    
    #include <QMainWindow>
    #include <QModbusDataUnit>
    
    QT_BEGIN_NAMESPACE
    
    namespace Ui
    { 
        class MainWindow;
    }
    
    class SettingDialog;
    class QModbusClient;
    class QModbusReply;
    
    
    QT_END_NAMESPACE
    
    class MainWindow : public QMainWindow
    { 
        Q_OBJECT
    
    public:
        MainWindow(QWidget *parent = nullptr);
        ~MainWindow();
    
        //信号与槽进行关联
        void initActions();
    
        //读请求数据包封装
        QModbusDataUnit readRequest() const;
    
    private slots:
        void onConnectButtonClicked();
    
        void onConnectTypeChanged(int);
    
        void onModbusStateChanged(int state);
    
        void onReadButtonClicked();
        void onReadReady();
    
    private:
        Ui::MainWindow *ui = nullptr;
    
        SettingDialog *m_settingDialog = nullptr;
    
        QModbusClient *modbusDevice = nullptr;
    
        QModbusReply *reply = nullptr;
    
    };
    #endif // MAINWINDOW_H

**mainwindow.cpp文件**

## 08. 程序下载 ##

8.1 [Qt RTU Master示例一.rar][Qt RTU Master_.rar]  
8.2 [RTUMasterTest(二).rar][RTUMasterTest_.rar]

## 09. 附录 ##

**9.1 Qt教程汇总**  
网址：[https://dengjin.blog.csdn.net/article/details/115174639][https_dengjin.blog.csdn.net_article_details_115174639]

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[Qt RTU Master_.rar]: https://download.csdn.net/download/dengjin20104042056/18859889
[RTUMasterTest_.rar]: https://download.csdn.net/download/dengjin20104042056/18882397
[https_dengjin.blog.csdn.net_article_details_115174639]: https://dengjin.blog.csdn.net/article/details/115174639